Multi-directional actuator

ABSTRACT

An apparatus is provided. The apparatus includes a bidirectional comb drive actuator. The apparatus may also include a cantilever. The cantilever includes a first end connected to the bidirectional comb drive actuator and a second end connected to an inner frame. In addition, the cantilever may include first and second conductive layers for routing electrical signals. Embodiments of the disclosed apparatuses, which may include multi-dimensional actuators, allow for an increased number of electrical signals to be routed to the actuators. Moreover, the disclosed apparatuses allow for actuation multiple directions, which may provide for increased control, precision, and flexibility of movement. Accordingly, the disclosed embodiments provide significant benefits with regard to optical image stabilization and auto-focus capabilities, for example in size- and power-constrained environments.

TECHNICAL FIELD

This disclosure relates to actuators in general, and in particular, tomicro-electro-mechanical-system (MEMS) actuators configured to move adevice.

BACKGROUND

Actuators may be used to convert electronic signals into mechanicalmotion. In many applications, such as, for example, portable electronicdevices, miniature cameras, optical telecommunications components, andmedical instruments, it may be beneficial for miniature actuators to fitwithin the specific size, power, reliability, and cost constraints ofthe application.

MEMS is a miniaturization technology that uses processes such asphotolithography and etching of silicon wafers to form highly precisemechanical structures with electronic functionality. MEMS actuatorsgenerally function in a similar fashion to conventional actuators butoffer some beneficial features over conventional actuators, and areformed using MEMS processes.

In some applications, such as moving an image sensor in a camera forautomatic focusing (AF) or optical image stabilization (OIS), anactuator may be used to move an optoelectronic device that has a numberof electrical inputs and outputs. For example, European patent No. EP0253375, entitled “Two-dimensional piezoelectric actuator,” by Fukada etal., teaches a design for a two-dimensional actuator that can be used tomove an image sensor in a plane. The actuator taught by Fukada, however,is large and unamenable to space-constrained applications. For example,Fukuda' s actuator may be used in large, stand-alone digital cameras,but not in miniature cell phone cameras, due to the associated spaceconstraints.

Unlike conventional piezoelectric actuators, MEMS actuators may be usedto, for example, move or position certain passive components withinminiature cell phone cameras. By way of example, U.S. Pat. No.8,604,663, entitled “Motion controlled actuator,” by Roman Gutierrez etal., and U.S. Patent Application No. 2013/0077945 A1, entitled“Mems-based optical image stabilization,” by Xiaolei Liu et al., teachMEMS actuators for moving a lens in a miniature camera (e.g., for use ina cell phone).

Neither of these MEMS actuators is able to move an optoelectronic devicethat has a number of electrical inputs and outputs. In addition, both ofthese MEMS actuators utilize deployment mechanisms that add complexity,size, and cost. Furthermore, conventional MEMS actuators are limited inthe number of electrical signals that may be routed thereto, typicallydue to the limited number of physical connections to the MEMS actuators.This limits the degree and type of movement that conventional MEMSactuators are able to achieve with respect to the passive components,and hence limits the overall effectiveness of conventional MEMSactuators.

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure is generally directed to actuators and relatedapparatuses. By way of example, such actuators may includebi-directional or multi-directional MEMS actuators for moving orpositioning a device, such as an image sensor in a camera. Variousembodiments of actuators disclosed herein make use of MEMS comb drivesand processes to achieve a high level of miniaturization, precision,power efficiency, and flexibility in terms of movement. Accordingly, theactuators of the present disclosure are highly suitable to, for example,provide optical image stabilization and auto-focus capabilities forcameras in space-constrained environments, such as within smartphones,and the like.

According to various embodiments of the disclosure, an apparatusincludes a bidirectional comb drive actuator and a cantilever havingfirst and second conductive layers for routing electrical signals. Thecantilever includes a first end connected to the bidirectional combdrive actuator, a second end connected to an inner frame, and first andsecond conductive layers. The bidirectional comb drive actuator, in oneembodiment, includes first and second frame pieces, and first and secondcomb drives. In one example implementation of the apparatus, the firstand second comb drives each include first and second comb finger arrays.The first comb finger array of the first comb drive may be connected tothe second frame piece. The second comb finger array of the first combdrive may be connected to the first frame piece. The first comb fingerarray of the second comb drive may be connected to the first framepiece. The second comb finger array of the second comb drive isconnected to the second frame piece. The first comb finger array of thefirst comb drive and the second comb finger array of the second combdrive, in one instance, are electrically coupled to a first potential.Further, the second comb finger array of the first comb drive iselectrically coupled to a second potential. In addition, the first combfinger array of the second comb drive is electrically coupled to a thirdpotential.

In one case, the first conductive layer of the cantilever iselectrically coupled to the second potential, and the second conductivelayer of the cantilever is electrically coupled to the third potential.The first conductive layer may be electrically isolated from the secondconductive layer. Moreover, in one embodiment of the actuator the firstconductive layer routes a first of the electrical signals to thebidirectional comb drive actuator and the second conductive layer routesa second of the electrical signals to the bidirectional comb driveactuator.

The bidirectional comb drive actuator, in another embodiment, includestwo or more comb drives. Each of the comb drives includes first andsecond curved comb finger arrays. In this embodiment, the bidirectionalcomb drive actuator also includes an inner flexure connected to thefirst end one of the cantilevers and a pair of outer flexures onopposite sides of the inner flexure.

Further embodiments of the disclosure include a multi-directionalactuator for moving a device. The multi-directional actuator includesone or more bidirectional comb drive actuators. Each of thebidirectional comb drive actuators includes two or more comb drives andfirst and second frame pieces. Each of the comb drives include first andsecond comb finger arrays. The first comb finger array of the first combdrive and the second comb finger array of the second comb drive areconnected to the second frame piece. The second comb finger array of thefirst comb drive and the first comb finger array of the second combdrive are connected to the first frame piece.

In one embodiment, the multidirectional actuator also includes an innerframe connected to the bidirectional comb drive actuators by one or morecantilevers. Each of the cantilevers in this embodiment includes routingfor a first electrical signal, and at least one of the cantileversfurther includes routing for a second electrical signal. Themulti-directional actuator may also include an outer frame connected tothe inner frame by one or more spring elements. The bidirectional combdrive actuators, in such an example, are attached to a central anchorthat may be mechanically fixed with respect to the outer frame. In oneimplementation, a platform mechanically fixes the central anchor withrespect to the outer frame. By way of example, the platform may be anoptoelectronic device or an image sensor.

In one embodiment of the multi-directional actuator, for each of thebidirectional comb drive actuators, the cantilevers electrically couplethe bidirectional comb drive actuator to one or more contact padsdisposed on the inner frame. Moreover, the spring elements electricallycouple the contact pads disposed on the inner frame to one or morecorresponding contact pads disposed on the outer frame.

Additional embodiments of the disclosure include methods for moving adevice using an actuator. One such method includes connecting an innerframe to one or more bidirectional comb drive actuators using acantilever for each of the bidirectional comb drive actuators. Themethod also includes coupling electrical signals to the bidirectionalcomb drive actuators using the cantilevers. Moreover, the methodincludes generating a controlled force using the bidirectional combdrive actuators and the electrical signals. The bidirectional comb driveactuators may include flexures. In such example implementations, for oneor more of the bidirectional comb drive actuators, coupling theelectrical signals to the bidirectional comb drive actuators includesusing the flexures to route the electrical signals.

In some of the disclosed methods, each of the bidirectional comb driveactuators include first and second comb drives. The first and secondcomb drives may each include first and second comb finger arrays. Somesuch methods may also include moving, in response to applying thecontrolled force, either the second comb finger array of the first combdrive and the first comb finger array of the second comb drive, or thefirst comb finger array of the first comb drive and the second combfinger array of the second comb drive.

The controlled force, in one case, effects movement in a plane, and thismovement includes linear movement. In other cases the movement includesrotational movement. Embodiments of the disclosed methods also includeapplying the controlled force between an outer frame and an inner frame,and mechanically fixing an anchor with respect to the outer frame. Insuch embodiments, the controlled force is applied to the anchor.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures.

FIG. 1 illustrates a plan view of a comb drive in accordance withexample embodiments of the present disclosure.

FIG. 2A illustrates a plan view of a comb drive actuator in accordancewith example embodiments of the present disclosure.

FIG. 2B illustrates a plan view of a bidirectional comb drive actuatorin accordance with example embodiments of the present disclosure.

FIG. 2C illustrates a plan view of a bidirectional comb drive actuatorin accordance with example embodiments of the present disclosure.

FIG. 3 illustrates a plan view of an actuator in accordance with exampleembodiments of the present disclosure.

FIG. 4A illustrates a plan view of an actuator in accordance withexample embodiments of the present disclosure.

FIG. 4B illustrates a cross-sectional view of a cantilever in accordancewith example embodiments of the present disclosure.

FIG. 5 illustrates a plan view of an actuator in accordance with exampleembodiments of the present disclosure.

FIG. 6 illustrates an operational flow diagram of a method in accordancewith example embodiments of the present disclosure.

FIG. 7 illustrates an operational flow diagram of a method in accordancewith example embodiments of the present disclosure.

The figures are provided for purposes of illustration only and merelydepict typical or example embodiments of the disclosure. The figures aredescribed in greater detail in the description and examples below tofacilitate the reader's understanding of the disclosed technology, andare not intended to be exhaustive or to limit the disclosure to theprecise form disclosed. It should be understood that the disclosure maybe practiced with modification or alteration, and that suchmodifications and alterations are covered by one or more of the claims,and that the disclosure may be limited only by the claims and theequivalents thereof. For clarity and ease of illustration, these figuresare not necessarily made to scale.

DETAILED DESCRIPTION

The present disclosure is directed to various embodiments of systems,methods, and apparatuses that include a MEMS actuator for moving adevice that may include electrical connections. The details of someexample embodiments of the systems, methods, and apparatuses of thepresent disclosure are set forth in the description below. Otherfeatures, objects, and advantages of the disclosure will be apparent toone of skill in the art upon examination of the present description,figures, examples, and claims. It is intended that all such additionalsystems, methods, apparatus, features, and advantages, etc., includingmodifications thereto, be included within this description, be withinthe scope of the present disclosure, and be protected by one or more ofthe accompanying claims.

In accordance with embodiments further described herein, variousactuators are provided. These actuators, including, in some instances,the packaging thereof, may be used in a range of different environments,for example, portable electronic devices, miniature cameras, opticaltelecommunications components, and medical instruments. The features ofthe disclosed actuators generally allow for a high degree of precisionand variability in moving or positioning a device in multiple degrees offreedom and multiple directions within these various environments, whileachieving low power consumption and being highly compact.

By way of example, in some embodiments, one aspect of such features ofthe disclosed actuators includes that the actuators allow for anincreased number of electrical signals to be routed to the actuators.Another aspect of such example features is that some embodiments of thedisclosed actuators include comb drives arranged in a back-to-backstructure that allows the actuators to effect movement in multipledirections. These features, in turn, may allow for increased control,precision, and flexibility over the degrees of freedom and number ofdirections in which the actuators may effect force or movement.Accordingly, the disclosed embodiments provide significant benefits withregard to optical image stabilization and auto-focus capabilities overconventional solutions, for example. Having provided a high-leveloverview of some aspects of the disclosed actuators, some examples ofbasic building blocks thereof will now be described.

Referring now to the figures, FIG. 1 illustrates a plan view of combdrive 10, in accordance with example embodiments of the presentdisclosure. Comb drive 10 may be an electrostatic comb drive. Comb drive10 may include comb finger arrays 15 and 16, which, by way of example,may be fabricated on silicon using MEMS processes such asphotolithography and etching.

As shown in FIG. 1, comb finger array 16 includes comb fingers 11 andspine 12 that connects comb fingers 11 to one another. Similarly, combfinger array 15 includes comb fingers 13 and spine 14 that connects combfingers 13 to one another. Comb fingers 11 and 13 may beinter-digitated, such that comb fingers 11 substantially line up withspaces 17 between comb fingers 13, and comb fingers 13 substantiallyline up with the spaces 18 between comb fingers 13. Comb fingers 11 and13, spines 12 and 14, and comb finger arrays 15 and 16 are illustratedin FIG. 1 as having particular shapes, proportions, spatialarrangements, etc., but one of skill in the art will recognizeadditional shapes, proportions, spatial arrangements, and so on, thatmay be utilized within the scope and spirit of the present disclosure.For example, while FIG. 1 illustrates comb fingers 11 and 13 without anyoverlap, comb fingers may be fabricated so that there is overlap.

In any case, when a voltage, charge, or electrical potential tension isapplied between comb fingers 11 and 13 (or between comb finger arrays 15and 16)—i.e., comb fingers 11 and/or 13, or comb finger arrays 15 and/or16, are electrified—comb finger arrays 15 and 16 may be attracted toeach other with an electrostatic force proportional to, by way ofexample, the square of the applied voltage (which may be positive ornegative as between comb finger arrays 15 and 16). This electrostaticforce may cause comb finger arrays 15 and 16 to move toward one another,while a spring restoring force may be used to separate comb fingerarrays 15 and 16 from one another. Additionally, the speed with whichcomb finger arrays 15 and 16 move with respect to one another may dependon the electrostatic force applied. Typically, the design of comb drive10 is such that comb fingers 11 and 13 may be pulled into an increasedoverlapping state by the electrostatic force between comb finger arrays15 and 16 or pulled into a decreased overlapping state by the springrestoring force. When comb finger arrays 15 and 16 overlap, comb fingers11 reside at least partially within space 17 of comb finger array 15,and comb fingers 13 reside at least partially within space 18 of combfinger array 16.

The ratio of comb finger width to depth may be chosen to avoid combfingers 11 bending into comb fingers 13 when comb fingers 11 and 13 areoverlapped. For example, comb fingers 11 and/or 13 may be about 6micrometers wide by about 150 micrometers long. In general, comb fingers11 and/or 13 may be between about 1 and 10 micrometers wide and about 20and 500 micrometers long. The distance between two adjacent comb fingers11 (or 13) subtracted by the width of one of the corresponding combfingers 13 (or 11) sets the total gap between comb fingers 11 and 13when brought into overlap by the electrostatic force. In some instances,it may be desirable for this total gap to be relatively small, in orderto increase the electrostatic force between comb fingers 11 and combfingers 13. In addition, it may also be desirable for the total gap tobe large enough to deal with variations in the width of comb fingers 11and/or 13 that arise from process variations. For example, the total gapmay be about 1 to 5 micrometers or larger. In various instances,however, the total gap may be made smaller or larger, as needed.Generally, comb drive 10 may be fabricated with a total gap that isbetween a minimum and a maximum value, but during motion, the total gapmay vary between the minimum and maximum values. In one particularimplementation of the disclosure, the total gap between comb fingers 11and 13 ranges from a minimum of about 1.5 micrometers to a maximum ofabout 4 micrometers, though narrower and wider ranges are possible.

The depth of comb fingers 11 and 13 may generally be limited by theparticular fabrication process used, and specifically by the etchingaspect ratio of that process—this is because it may generally bedesirable for the width of comb fingers 11 and 13 on the top to besubstantially the same as the width of comb fingers 11 and 13 on thebottom. The depth aspect of comb fingers 11 and 13 is not illustrated inFIG. 1, but would extend into or out of the page. For example, combfingers 11 and 13 may be about 50 to 250 micrometers in depth. Spaces 17and 18 may either be etched away entirely, or may be removed by othermethods known in the art of MEMS micromachining. Other variations ofcomb drive 10's length, shape, arrangement, and configuration may beused to achieve differing degrees, directions, and/or precision ofcontrolled forces, various size footprints, and other characteristics,as will be appreciated by one of skill in the art upon studying thepresent disclosure.

FIG. 2A illustrates a plan view of comb drive actuator 20 in accordancewith example embodiments of the present disclosure. As shown in FIG. 2A,comb drive actuator 20 includes comb drive 10. Some details of combdrive 10 are omitted here for simplicity, but are illustrated in FIG. 1,and will be clear to one of skill in the art upon studying the presentdisclosure. Referring again to FIG. 2A, comb drive 10 includes combfinger arrays 15 and 16. One embodiment of comb drive actuator 20 alsoincludes first and second frame pieces 22 a/b, and first and secondflexures 24 a/b. Although not shown in detail in FIG. 2A, to providecontext with respect to first and second comb finger arrays 15 and 16,it will be understood that, as shown in FIG. 1, comb fingers 11 and 13extend substantially from left to right, and vice versa, in comb fingerarrays 15 and 16. Moreover, although not explicitly shown in FIG. 2A, itwill be understood that spines 12 and 14 run substantially verticallyfrom first frame piece 22 a to second frame piece 22 b (i.e.,substantially in parallel with flexures 24 a/b depicted in FIG. 2A).Spine 14 of comb finger array 15 may be attached to second frame piece22 b, while spine 12 of comb finger array 16 may be attached to firstframe piece 22 a. When spine 14 or of comb finger array 15 or 16 isattached to either of first or second frame piece 22 a/b, it may be saidthat comb finger array 15 or 16 is connected to first or second framepiece 22 a/b.

Configured as such, when comb finger arrays 15 and 16 are attracted toor repelled from one another such that movement occurs, first and secondframe pieces 22 a/b may likewise be caused to move (e.g., from left toright or vice versa in FIG. 2A). For example, assuming comb finger array15 is fixed relative to comb finger array 16, if a voltage is applied tocomb finger array 16 relative to comb finger array 15 (or vice versa),comb finger array 16 may be attracted to comb finger array 15, such thatcomb finger array 16 may be induced to move toward comb finger array 15.This in turn may cause first frame piece 22 a to move toward the side ofcomb drive 10 where comb finger array 15 resides (i.e., to the left inthe plane of comb drive actuator 20 in FIG. 2A).

In another example, assuming comb finger array 16 is fixed relative tocomb finger array 15, if a voltage is applied to comb finger array 15relative to comb finger array 16 (or vice versa), comb finger array 15may be attracted to comb finger array 16, such that comb finger array 15may be induced to move toward comb finger array 16. This in turn maycause second frame piece 22 b to move toward the side of comb drive 10where comb finger array 16 resides (i.e., to the right in FIG. 2A). Oneof skill in the art will appreciate, upon studying the presentdisclosure, that electrostatic forces and other motive forces may bedeveloped between comb finger arrays 15 and 16 by methods other thanapplying voltage, without departing from the spirit of the presentdisclosure. For example, charge may be applied to comb finger arrays 15and 16.

The movement of first and/or second frame pieces 22 a/b and of combfinger arrays 15 and/or 16 may be directed and/or controlled to someextent by first and second flexures 24 a/b. Specifically, first andsecond flexures 24 a/b may be substantially flexible or soft in thehorizontal direction (i.e., in the direction of comb fingers 11 and 13)and may be substantially stiff or rigid in the vertical direction (i.e.,in the direction of spines 12 and 14). In this example configuration offlexibility and rigidity, first and second flexures 24 a/b allow combdrive 10 to effect movement horizontally (i.e., in the left/right,east/west, direction in FIG. 2A) while substantially restricting themovement in the vertical direction (i.e., in the top/bottom,north/south, direction in FIG. 2A). First and second flexures 24 a/b maybe omitted in some instances, and, in other instances, may be replacedby various motion control means known in the art and/or appreciated inlight of the present disclosure.

As mentioned above, one embodiment of comb drive actuator 20 includesfirst and second flexures 24 a/b that direct the motion of comb fingerarrays 15 and 16 to be substantially parallel to the length of combfingers 11 and 13 (i.e., east/west in FIG. 2A). The arrangement of firstand second flexures 24 a/b may be referred to, in some cases, as adouble parallel flexure motion control. Such a double parallel flexuremotion control may produce nearly linear motion, but there may be aslight run-out known as arcuate motion. Nevertheless, the gap on oneside of comb fingers 11 may not be equal to the gap on the other side ofcomb fingers 11, and this may be used advantageously in design tocorrect for effects such as arcuate motion of a double parallel flexuremotion control.

Referring again to one embodiment of comb drive actuator 20, first andsecond flexures 24 a/b form a motion control that is a double parallelflexure. Nevertheless, as alluded to above, the motion control may beimplemented using other structures that serve to control the motion offirst and second frame pieces 22 a/b with respect to one another. In theillustrated embodiment, first and second flexures 24 a/b include thinnerportions on the respective ends thereof. These thinner portions mayallow bending when, for example, there is a translation of first framepiece 22 a with respect to second frame piece 22 b or vice versa (i.e.,in the east/west direction in FIG. 2A).

In terms of example dimensions, the thicker portion of first and secondflexures 24 a/b may be about 10 to 50 micrometers wide, and the thinnerportions may be about 1 to 10 micrometers wide. In various embodiments,any number and type of motion controls may be used as desired to controlor limit the motion of comb finger arrays 15 and/or 16. Controlledmotion may enhance the overall precision with which comb drive actuator20 effects movement, or positions a device such as, for example, andimage sensor in a smartphone camera. In addition, controlled motion aidsin avoiding a situation in which comb fingers 11 and 13 snap together.For example, controlled motion may generally be effected by creating alower level of stiffness in desired direction of motion of comb fingers15 and 16, while creating a higher level of stiffness in the directionorthogonal to the motion of comb fingers 15 and 16 in the plane of combdrive actuator 20. By way of example, this may be done using a doubleparallel flexure type motion control, as described in further detailherein, e.g., in connection with at least FIGS. 2A and 2B.

With respect to various example implementations of comb drive actuator20, it may be typical that first frame piece 22 a is mechanically fixedwith respect to second frame piece 22 b, or vice versa, for example,through first and second flexures 24 a and 24 b. In this manner, whencomb fingers 11 and 13 (or comb finger arrays 15 and 16) are electrified(e.g., as described above), one of first frame piece 22 a and secondframe piece 22 b is moved from an initial position while the otherremains fixed. Once comb fingers 11 and 13 are no longer electrified,whichever of first or second frame piece 22 a or 22 b moved from theinitial position, returns thereto. In this case, the spring restoringforce is provided by first and second flexures 24 a and 24 b. As such,comb drive actuator 20 may be referred to as a unidirectional comb driveactuator.

In terms of dimensions, spines 12 and 14 and first and second framepieces 22 a/b, in various instances, may be designed wide and deepenough to be rigid and not flex substantially under an applied range ofelectrostatic or other motive forces. For example, spines 12 and 14 maybe about 20 to 100 micrometers wide and about 50 to 250 micrometersdeep, and first and second frame pieces 22 a/b may be larger than about50 micrometers wide and about 50 to 250 micrometers deep.

FIG. 2B illustrates a plan view of bidirectional comb drive actuator 21in accordance with example embodiments of the present disclosure. As aninitial matter, it will be noted that, throughout the presentdisclosure, like-numbered elements as between the various figures maygenerally be substantially similar in nature, and letters—e.g., a, b, c,etc.—may be used to denote various instances of these elements. Anyexceptions to this generality will either be explained herein, and/orwill be apparent to one of ordinary skill in the art upon studying thepresent disclosure.

As shown in FIG. 2B, one embodiment of bidirectional comb drive actuator21 includes comb drives 10 a/b. Additional embodiments may include firstand second frame pieces 22 a/b and/or first and second flexures 24 a/b.Some details of comb drives 10 a/b are illustrated in FIG. 1 with regardto comb drive 10. Although not all of the details of each of comb drives10 a/b are shown in FIG. 2B, in the illustrated embodiment (and variousrelated embodiments), it will be understood that, for example, spine 12(shown in FIG. 1) of comb drive 10 a is connected to first frame piece22 a and spine 14 (shown in FIG. 1) of comb drive 10 a is connected tosecond frame piece 22 b. It will further be understood that, in thisparticular embodiment, spine 12 of comb drive 10 b is connected tosecond frame piece 22 b and spine 14 of comb drive 10 b is connected tofirst frame piece 22 a. In other words, comb finger arrays 15 a and 16 bare connected to second frame piece 22 b, and comb finger arrays 15 band 16 a are connected to first frame piece 22 a.

In this manner, and in this example implementation of bidirectional combdrive actuator 21, when comb finger arrays 15 a and 16 a are electrified(e.g., in the manner described above), a motive force is applied withrespect to first and second frame pieces 22 a/b such that either firstor second frame piece 22 a/b moves substantially horizontally from aninitial position with respect to second or first frame piece 22 b/a,depending, by way of illustration, on which of first and second framepiece 22 a/b is mechanically fixed. Once comb finger arrays 15 a and 16a are no longer electrified, first or second frame pieces 22 a/b moveback to the initial state due to the spring restoring force of first andsecond flexures 24 a and 24 b. In other words, comb drive 10 a mayeffect unidirectional movement in a similar fashion as described abovewith respect to comb drive 10. Further to this implementation,bidirectional movement is achieved when, in addition to the movementresulting from comb drive 10 a—e.g., in a first direction—comb drive 10b similarly achieves movement—e.g., in a second, substantially oppositedirection—when comb finger arrays 15 b and 16 b are electrified.

In one example implementation, comb finger arrays 15 a and 16 b may betied to a common potential (e.g., ground or some other positive ornegative voltage) that acts as a reference for comb finger arrays 16 aand 15 b. Given this reference, comb finger arrays 16 a and 15 b may beelectrified, by way of illustration, depending on the direction ofmovement required. This may entail applying a positive or negativevoltage (e.g., relative to ground or other common reference applied tocomb finger arrays 15 a and 16 b) of a magnitude to comb finger array 16a, hence causing comb finger array 16 a to be attracted to comb fingerarray 15 a. Assuming second frame piece 22 b is fixed, this attractionwould, in this instance, cause first frame piece 22 a to move to theleft in FIG. 2B. Further to this illustration, electrifying comb fingerarray 15 b may entail applying thereto a positive or negative voltage(again, e.g., relative to the common reference applied to comb fingerarrays 15 a and 16 b) of the same magnitude as the voltage applied tocomb finger array 16 a, hence causing comb finger array 15 b to beattracted to comb finger array 16 b. This attraction would, in thisinstance, cause first frame piece 22 a to move to the right in FIG. 2B,assuming again that second frame piece 22 b is fixed.

It will be appreciated, however, that in another embodiment, comb fingerarrays 16 a and 15 b may be tied to a common potential that acts as areference for comb finger arrays 15 a and 16 b. Given this reference,comb finger arrays 15 a and 16 b may be electrified to effectbidirectional movement of first frame piece 22 a with respect to secondframe piece 22 b or vice versa, depending on which of first or secondframe pieces 22 a/b is fixed (in a fashion similar to that describedabove). In further embodiments, the motive force developed by comb drive10 a may differ from the motive force developed by comb drive 10 b. Forexample, voltages of different magnitudes may be applied to comb fingerarrays 16 a and 15 b, or whichever comb finger arrays are not tied to acommon potential. It will be understood that, in some instances, forcomb finger arrays 16 a and 15 b to maintain different voltage levels,or electrostatic or charge states, comb finger arrays 16 a and 15 b maybe electrically separate (or isolated) from one another.

In various embodiments, spines 12 and 14 of comb finger arrays 15 a/band 16 a/b may be attached to first and/or second frame pieces 22 a/b indifferent configurations to achieve different purposes. For example, inone embodiment, for each of comb drives 10 of a set of comb drives,spine 12 is attached to first frame piece 22 a while spine 14 isattached to second frame piece 22 b. Such a configuration results in aparallel cascade of comb drives 10 that may increase the electrostaticforce ultimately applied to first and second frame pieces 22 a/b. Inanother example embodiment, comb drives 10 in a set of comb drives arearranged in a back-to-back fashion to achieve bi-directional movement,as described above. While this back-to-back arrangement was describedabove with regard comb drives 10 a/b—i.e., two comb drives 10—any largernumber of comb drives may be used to achieve bi-directional movement.

FIG. 2C illustrates a plan view of bidirectional comb drive actuator 23in accordance with example embodiments of the present disclosure.Bidirectional comb drive actuator 23 may be considered somewhat similarin nature to bidirectional comb drive actuator 21, but there are somedistinguishing features. For example, bidirectional comb drive actuator23 includes comb drives 10 c/d, and in some embodiments, includes outerflexures 24 c/d and inner flexure 24 e. As shown, comb drives 10 c/d maytaper from a wider end (e.g., toward to the openings between outerflexures 24 c/d and inner flexure 24 e) to a narrower end (e.g., towardthe juncture or pivot point of outer flexures 24 c/d and inner flexure24 e). As further illustrated, each of outer flexures 24 c/d and innerflexure 24 e in this embodiment includes a relatively thin portion thatextends from the pivot point.

In one instance, comb drive 10 c includes comb finger arrays 15 c and 16c, and comb drive 10 d includes comb finger arrays 15 d and 16 d. Eachof comb finger arrays 15 c/d and 16 c/d may include respective curvedcomb fingers 1113 c/d that are substantially curved, for example, alongan arc as illustrated at the wider end of comb drives 10 c/d.Specifically, one implementation of curved comb fingers 1113 c/d isshown in greater detail toward the narrower end of (or pivot pointbetween) comb drives 10 c/d. In one instance of the disclosure, zipperactuators may be placed near the pivot point and may be used inconjunction with comb drives 10 c/d to increase the motive force betweencomb finger arrays 15 c and 16 c and/or 15 d and 16 d. In a fashionsimilar to bidirectional comb drive actuator 21 (described above), combfinger arrays 15 c/d and 16 c/d of bidirectional comb drive actuator 23may be electrified to effect bidirectional movement.

With respect to bidirectional comb drive actuator 23, however, theresulting movement is substantially rotational. Rotational movement maybe effective in avoiding arcuate motion, and may be converted to linearmotion, for example using cantilevers (e.g., as shown in FIG. 5). In oneexample implementation of bidirectional comb drive actuator 23, if outerflexures 24 c/d are made stiff, inner flexure 24 e may be made flexibleso that inner flexure 24 e may bend along the relatively thin portionnear the pivot point when comb finger arrays 15 c/d and/or 16 c/d areelectrified. If, on the other hand, in another example implementation,outer flexures 24 c/d are made flexible, inner flexure 24 e may be madestiff so that outer flexures 24 c/d may bend along the relatively thinportions near the pivot point when comb finger arrays 15 c/d and/or 16c/d are electrified. Various additional modifications may be made tobidirectional comb drive actuator 23, as will be understood by one inthe art upon studying the present disclosure.

FIG. 3 illustrates a plan view of apparatus 30 in accordance withexample embodiments of the present disclosure. The embodiment ofapparatus 30 illustrated in FIG. 3 includes four bidirectional combdrive actuators 21. In other example implementations, apparatus 30 mayinclude any number of bidirectional comb drive actuators 21. Apparatus30 may be, by way of example, a multi-dimensional actuator. For the mostpart, the numbered elements of FIG. 3 have been described in detailabove with regard to FIGS. 1, 2A, and 2B, and the details of suchdescription will not be repeated here. Nevertheless, additional aspectsof these elements will be described with regard to FIG. 3 whereappropriate. Additional elements of apparatus 30 will also be described.

For example, in addition to bidirectional comb drive actuators 21,apparatus 30 may also include anchor 32 and electrical contact pads 86 aand 86 b. Anchor 32 may be rigidly connected or attached to first and/orsecond frame pieces 22 a/b of one or more bidirectional comb driveactuators 21, such that anchor 32 is mechanically fixed with respectthereto. Thus, for example, if first frame piece 22 a is connected orattached to anchor 32, movement of second frame piece 22 b relative tofirst frame piece 22 a may also be considered movement relative toanchor 32. In this embodiment illustrated in FIG. 3, second frame piece22 b is connected or attached to anchor 32. For example, second framepiece 22 b may be an integral part of anchor 32.

Electrical contact pads 86 a and 86 b are shown in FIG. 3 for conceptualpurposes only, in order to provide context for some of the electricalrouting aspects described in connection with apparatuses 30 and 40. Invarious embodiments, and as described further below with regard to FIG.4A, each of electrical contact pads 86 a and 86 b may reside on innerframe 46 or outer frame 48 (see, e.g., electrical contact pads 82 and 84in FIG. 4A). For example, electrical contact pads 86 a and 86 b may beimplemented in a fashion similar to electrical contact pads 82 and/or84. Electrical contact pads 86 a and 86 b, however, are presented onlyconceptually in FIG. 3. Therefore, for example, it should not be assumedthat electrical contact pads 86 a or 86 b are mechanically fixed withrespect to any of bidirectional comb drive actuators 21. Rather, as isdescribed below with regard to FIG. 4A, electrical contact pads 86 a and86 b (see, e.g., electrical contact pads 82 and 84 in FIG. 4A) may berouted to one or more of bidirectional comb drive actuators 21 throughone or more cantilevers 44 a-d. In this manner, electrical contact padsmay be either fixed or free to move in various degrees of freedom withrespect to bidirectional comb drive actuators 21 illustrated in FIG. 3,regardless of whether electrical contact pads 86 a and 86 reside oninner frame 46, outer frame 48, or elsewhere.

In various embodiments of apparatus 30, the length, size, or proportionof the various bidirectional comb drive actuators 21 included inapparatus 30 may vary, for example to accommodate spatial constraints(e.g., to minimize or customize the footprint of apparatus 30). By wayof illustration, a first bidirectional comb drive actuator 21 (e.g., inthe upper left quadrant of apparatus 30) may be relatively long andnarrow, while a second bidirectional comb drive actuator 21 (e.g., inthe lower left quadrant) may be shorter and wider. As such, in the casewherein first and second bidirectional comb drive actuators 21 of thisillustrative example are perpendicular to one another, the relativeproportions may maximize the usage of allotted space. Otherconfigurations, lengths, sizes, and proportions are possible and will berecognized by one of skill in the art upon studying the presentdisclosure. Moreover, further aspects of apparatus 30 will become clearwhen viewed in conjunction with the description of FIG. 4A, includingfor example, how apparatus 30 may be used to achieve multidirectionalmovement.

FIG. 4A illustrates a plan view of apparatus 40 in accordance withexample embodiments of the present disclosure. Apparatus 40, in variousembodiments, is a multi-dimensional actuator. As illustrated in FIG. 4A,one embodiment of apparatus 40 includes one or more bidirectional combdrive actuators 21 a-d. One embodiment of actuator 40 also includes oneor more cantilevers 44 a-d. Cantilevers 44 a-d each include a first endconnected to one of bidirectional comb drive actuators 21 a-d, and asecond end connected to inner frame 46. As shown in FIG. 4A, oneembodiment of apparatus 40 includes outer frame 48 connected to innerframe 46 by one or more spring elements 80. Additionally, bidirectionalcomb drive actuators 21 a-d are, in one embodiment, connected to anchor42, in a fashion substantially similar as described above with regard toFIG. 3.

Further to this embodiment, bidirectional comb drive actuators 21 a-dmay apply a controlled force between inner frame 46 and anchor 42. Oneor more bidirectional comb drive actuators 21 a-d may be rigidlyconnected or attached to anchor 42, and anchor 42 may be mechanicallyfixed (e.g., rigidly connected or attached) with respect to outer frame48. In one embodiment, a platform is rigidly connected or attached toouter frame 48 and to anchor 42. In this manner, the platform maymechanically fix outer frame 48 with respect to anchor 42 (and/or viceversa). Inner frame 46 may then move with respect to both outer frame 48and anchor 42, and also with respect to the platform. In one embodiment,the platform is a silicon platform. The platform, in variousembodiments, is an optoelectronic device, or an image sensor, such as acharge-coupled-device (CCD) or a complementary-metal-oxide-semiconductor(CMOS) image sensor.

The size of apparatus 40 may be substantially the same as the size asthe platform, and the platform may attach to outer frame 48 and anchor42, thus mechanically fixing anchor 42 with respect to outer frame 48.In one example implementation, the platform is the OV8835 image sensorfrom Omni Vision with an optical format of 1/3.2″. In thisimplementation, the size of both apparatus 40 and the platform can beequal to about 6.41 mm by 5.94 mm. In one embodiment of apparatus 40,the platform is smaller than apparatus 40, and the platform attaches toinner frame 46. In this particular embodiment, outer frame 48 is fixed(or rigidly connected or attached) relative to anchor 42, and innerframe 46 is moved by the various bidirectional comb drive actuators 21a-d.

In one instance, cantilevers 44 a-d are relatively stiff in therespective direction of motion of the respective bidirectional combdrive actuators 21 a-d, and are relatively soft in the in-planeorthogonal direction. This may allow for bidirectional comb driveactuators 21 a-d to effect a controlled motion of inner frame 46 withrespect to anchor 42 and hence with respect to outer frame 48. Outerframe 48, in some implementations of apparatus 40, is not continuousaround the perimeter of apparatus 40, but is broken into two, three, ormore pieces. Similarly, inner frame 46 may be continuous or may bedivided into sections, in various embodiments.

As shown in FIG. 4A, there may be four bidirectional comb driveactuators 21 a-d. In one embodiment, two bidirectional comb driveactuators 21 a/d actuate in positive and/or negative aspects of a firstdirection (east/west, or left/right) in the plane of apparatus 40, andtwo bidirectional comb drive actuators 21 b/c actuate positive and/ornegative aspects of a second direction (north/south, or top/bottom) inthe plane of apparatus 40. The first and second directions may besubstantially perpendicular to one another in the plane of apparatus 40.Various other configurations of bidirectional comb drive actuators 21a-d are possible. Such configurations may include more or less combdrives 10 in each of the bidirectional comb drive actuators 21 a-d, andvarious positioning and/or arrangement of bidirectional comb driveactuators 21 a-d, for example, to enable actuation in more or lessdegrees of freedom (e.g., in a triangular, pentagonal, hexagonalformation, or the like), as will be appreciated by one of skill in theart upon studying the present disclosure. In one embodiment, any ofbidirectional comb drive actuators 21 a-d may be replaced with combdrive actuators 20 or bidirectional comb drive actuators 23 a-d.

FIG. 4B illustrates a cross-sectional view of a portion of cantilever 44in accordance with example embodiments of the present disclosure. In theillustrated embodiment, at least a portion of cantilever 44 includesmultiple conductive layers. As illustrated in FIG. 4B, cantilever 44 mayinclude first and second conductive layers 45 and 47, and first andsecond insulating layers 43 and 49. First and second conductive layers45 and 47 may, in some example implementations, serve as routing layersfor electrical signals, and may include poly silicon and/or metal.Insulating layers 43 and 49 may provide structure for first and secondconductive layers 45 and 47.

In one example implementation of cantilever 44, insulating layers 43 and49 include silicon dioxide, second conductive layer 57 includes metal,and first conductive layer includes polysilicon. In a variant of thisexample, a coating (e.g., oxide or the like) may cover second conductivelayer 47, e.g., to provide insulation against shorting out when cominginto contact with another conductor. Second insulating layer 49 may be athin layer that includes oxide and/or the like. Additionally, firstconductive layer 45, in some instances, may be relatively thick(compared to the other layers of cantilever 44), and may, for example,include silicon, polysilicon, metal, and/or the like. In such instances,first conductive layer 45 may contribute more than the other layers tothe overall characteristics of cantilever 44, including, e.g., thenature, degree, and/or directionality of the flexibility thereof.Additional embodiments of cantilever 44 (and indeed cantilevers 44 a-d)may include additional conductive layers, such that additionalelectrical signals may be routed via the cantilever 44. In generally,some embodiments of cantilevers 44 a-d may be manufactured in a similarfashion to flexures 24 a/b, though the sizing may be different betweenthe two. Moreover, one of skill in the art will appreciate additionalmaterials that may be used to form the various layers of cantilever 44without departing from the spirit of the disclosure.

Referring again to FIG. 4A, one or more of bidirectional comb driveactuators 21 a-d may apply a controlled force (e.g., a motive force, oran electrostatic force developed from a voltage, as described above)between outer frame 48 and inner frame 46. Embodiments of apparatus 40may be suitable for moving a device (not shown) having electricalconnections, because apparatus 40 enables precise, controlled, andvariable motive forces to be applied between inner and outer frames 46and 48 in multiple directions (including vertical, horizontal, forexample) and degrees of freedom, and because apparatus 40 may beimplemented using a highly compact footprint. Using various combinationsand degrees of vertical and horizontal motive forces, apparatus 40 mayachieve combinations of linear and rotational movement. Moreover,apparatus 40 may utilize MEMS devices for reduction in power.Accordingly, apparatus 40 provides multiple benefits over conventionalsolutions to optical image stabilization and autofocus applicationsconstrained by size, power, cost, and performance parameters, such as insmartphone and other applications described herein.

As described above with regard to FIG. 2B, various motive forces may bedeveloped using bidirectional comb drive actuators 21 a-d. In someembodiments, in order to develop a number of options relating to thesemotive forces, multiple different electrical signals may be used. By wayof example, various motive forces may be used to achieve translational,multi-directional, diagonal, and/or rotational movement in the plane ofapparatus 40—e.g., such movement may be manifested by inner frame 46relative to outer frame 48 and/or anchor 42. The number of possiblecombinations of various motive forces may generally increase the levelof control of and precision over the movement achieved using apparatus40. As such motive forces may typically be developed using a number ofelectrical signals, embodiments for routing these electrical signalsthroughout apparatus 40 will now be described.

As illustrated in FIG. 4A, one embodiment of apparatus 40 involvesconnecting inner frame 46 to outer frame 48 by one or more springelements 80. Spring elements 80 may be electrically conductive and maybe soft in all movement degrees of freedom. In various embodiments,spring elements 80 route electrical signals between electrical contactpads 82 on outer frame 48 to electrical contact pads 84 on inner frame46. In example implementations, spring elements 80 come out from innerframe 46 in one direction, two directions, three directions, or in allfour directions.

In one embodiment, apparatus 40 is made using MEMS processes such as,for example, photolithography and etching of silicon. Apparatus 40, insome cases, moves +/−150 micrometers in plane, and spring elements 80may be designed to tolerate this range of motion without touching oneanother (e.g., so that separate electrical signals can be routed on thevarious spring elements 80). For example, spring elements 80 may beS-shaped flexures ranging from about 1 to 5 micrometers in thickness,about 2 to 20 micrometers wide, and about 150 to 1000 micrometers byabout 150 to 1000 micrometers in the plane.

In order for spring elements 80 to conduct electricity well with lowresistance, spring elements 80 may contain, for example, heavily dopedpolysilicon, silicon, metal (e.g., aluminum), a combination thereof, orother conductive materials, alloys, and the like. For example, springelements 80 may be made out of polysilicon and coated with a roughly2000 Angstrom thick metal stack of Aluminum, Nickel, and Gold. In oneembodiment, some spring elements 80 are designed differently from otherspring elements 80 in order to control the motion between outer frame 48and inner frame 46. For example, four to eight (or some other number) ofspring elements 80 may have a device thickness between about 50 and 250micrometers. Such a thickness may somewhat restrict out-of-planemovement of outer frame 48 with respect to inner frame 46.

In various embodiments, the electrical signals may be delivered tobidirectional comb drive actuators 21 a-d via routing on and/or incantilevers 44 a-d. As described above, in some instances, two or moredifferent voltages may be used in conjunction with bidirectional combdrive actuator 21 a. In such instances, two electrical signals may berouted to bidirectional comb drive actuator 21 a via first and secondconductive layers 45 and 47, respectively, of cantilever 44 a. Oncedelivered to bidirectional comb drive actuator 21 a, the two electricalsignals may be routed, for example, via first frame piece 22 a, to combfinger arrays 16 a and 15 b, respectively.

In another example implementation of apparatus 40, two electricalsignals used to develop motive forces in bidirectional comb driveactuator 21 b may also be used to develop similar motive forces inbidirectional comb drive actuator 21 c. In such an implementation,rather than routing in these two electrical signals to bidirectionalcomb drive actuator 21 c through cantilever 44 c, the two electricalsignals may be routed to bidirectional comb drive actuator 21 c frombidirectional comb drive actuator 21 b. By way of example, and referringin part to the numbered components of FIG. 3, this may entail routingthe two electrical signals from electrical contact pad 86 a or 86 b,through cantilever 44 b to first frame piece 22 a of bidirectional combdrive actuator 21 b. In addition, the two electrical signals may berouted from first frame piece 22 a via flexures 24 a/b (respectively)and second frame piece 22 b to anchor 32 (or 42 in FIG. 4A). The twoelectrical signals may then be routed through anchor 42 to bidirectionalcomb drive actuator 21 c. It will be appreciated that various routingoptions may be exploited to deliver electrical signals to bidirectionalcomb drive actuators 21 a-d. For example, multiple routing layers may beutilized in anchor 42, in first or second frame pieces 22 a/b, and/or infirst and second flexures 24 a/b.

Having described various implementations that may be used to route anddistribute electrical signals throughout apparatus 40, the use of thesesignals to achieve various types of movements in the plane of apparatus40 will now be described. In one example, various degrees oftranslational movement in a first horizontal direction (e.g., left) maybe achieved by applying a first voltage to bidirectional comb driveactuators 21 a/d (e.g., to respective comb finger arrays 16 a relativeto comb finger arrays 15 a). To illustrate, a first electrical signal ofbetween zero and 45 volts, variable with 14-bit resolution, may beapplied to bidirectional comb drive actuators 21 a/d.

In a substantially similar fashion, a second voltage may be applied tobidirectional comb drive actuators 21 a/d (e.g., to respective combfinger arrays 15 b relative to comb finger arrays 16 b) to achievetranslational movement in a second horizontal direction (e.g., right).As such, the combination of first and second electrical signals in thisexample allow for bidirectional movement in the plane of apparatus 40with varying degrees of force according to an available bit resolutionof each of the electrical signals. It will be noted that, forsubstantially horizontal movement, whether left or right, equal motiveforces may be generated by bidirectional comb drive actuators 21 a/d,and hence equal (or opposite) voltages may be applied.

Building upon this example, it will be understood that vertical(north/south) movement in the plane of apparatus 40 may be achieved in asubstantially similar fashion as described above for horizontal movement(east/west). For instance, delivering one or more electrical signals tobidirectional comb drive actuators 21 b/c may effect movementperpendicularly in the plane of apparatus 40 with to respect to themovement effected by bidirectional comb drive actuators 21 a/d. Inshort, as described in these examples, combinations of bidirectionalcomb drive actuators 21 a/d and 21 b/c may be used to effecttranslational movement either horizontally (left/right or east/west) orvertically (top/bottom or north/south), in the plane of apparatus 40. Infurther embodiments, diagonal movement may be achieved in the plane ofapparatus 40 by effecting vertical movement with bidirectional combdrive actuators 21 b/c, and, at the same time, by effecting horizontalmovement with bidirectional comb drive actuators 21 a/d. Thus, diagonalmovement may include aspects of movement in both the horizontaldirection (east/west) and the vertical direction (north/south) at thesame time (e.g., diagonal movement may include northeast or southwest,etc., in the plane of apparatus 40).

In still further embodiments, rotational movement (about the z-axis inthe plane of apparatus 40) may be achieved by using additionalcombinations of electrical signals in conjunction with combinations ofbidirectional comb drive actuators 21 a-d. If, for example, equal andopposite motive forces are developed by bidirectional comb driveactuators 21 a/b, clockwise or counterclockwise rotational movement maybe effected. By way of illustration, if a motive force is developed inbidirectional comb drive actuator 21 a to effect movement to the right,and a motive force is developed by bidirectional comb drive actuator 21d to effect movement to the left, the combination of these motive forcesmay achieve clockwise rotational movement. Counterclockwise movement maybe achieved by developing motive forces in the opposite direction of theprevious example—e.g., using voltages of opposite polarity. Rotationalmovement may likewise be achieved using bidirectional comb driveactuators 21 c/d. Rotation and translation may be achieved incombination by, for example, in addition to developing equal andopposite motive forces by bidirectional comb drive actuators 21 a/d,concurrently developing a vertical motive force using bidirectional combdrive actuators 21 b/c.

In yet another embodiment, a combination of rotational and diagonalmovement may be achieved in the plane of apparatus 40. By way ofexample, and in contrast to the purely rotation movement exampledescribed above, opposite motive forces of unequal magnitudes may bedeveloped by bidirectional comb drive actuators 21 a/d. In the case ofthe motive force developed by bidirectional comb drive actuator 21 abeing to the right (east) and being greater in magnitude than the motiveforce developed by bidirectional comb drive actuator 21 d, which in thisexample would be to the left (west), a clockwise rotational movementwould be achieved with simultaneous movement in the upper right diagonaldirection (northeast) in the plane of apparatus 40. Further adaptationsof such movement combinations will be apparent to one of skill in theart upon studying the present disclosure.

FIG. 5 illustrates a plan view of apparatus 50 in accordance withexample embodiments of the present disclosure. Apparatus 50, in variousembodiments, is a multi-dimensional actuator. As shown, one embodimentof apparatus 50 includes one or more bidirectional comb drive actuators23 a-d. Actuator 50 may also include one or more cantilevers 54 a-d.Each of the cantilevers 54 a-d includes a first end connected to one ofthe bidirectional comb drive actuators 23 a-d and a second end connectedto inner frame 56. Moreover, in some implementations, at least one ofcantilevers 54 a-d includes first and second conductive layers (see,e.g., FIG. 4B and associated description) for routing electricalsignals. As further illustrated, one embodiment of apparatus 50 includesanchor 52, to which one of outer flexures 24 c/d for each bidirectionalcomb drive actuator 23 a-d may be connected.

As illustrated in FIG. 5 and explained with reference to FIG. 2C, eachbidirectional comb drive actuator 23 a-d may be designed so as togenerate rotational movement in the plane of apparatus 50 when combfinger arrays 15 c/d and/or 16 c/d are electrified. In one exampleimplementation of apparatus 50, cantilevers 54 a-d convert thisrotational movement to substantially linear movement that issubstantially orthogonal (in the plane of apparatus 50) to the portionof inner frame 56 to which the respective cantilever 54 a-d isconnected. Comb finger arrays 15 c/d and 16/cd of comb drives 10 c/d,for example within bidirectional comb drive actuator 23 a may beelectrified to effect rotation movement of inner flexure 24 e.Cantilever 54 a may be connected to inner flexure 24 e, which may pushcantilever 54 a up (i.e., vertically in the positive y, or north,direction in the plane of apparatus 50 in FIG. 5) toward inner frame 56or pull cantilever 54 a down (i.e., vertically in the negative y, orsouth, direction in the plane of apparatus 50 in FIG. 5) toward innerframe 56.

Continuing the example, cantilever 54 a may be stiff along the lengththereof (i.e., vertically, or north/south, in the plane of apparatus 50)but soft transverse to the length thereof (i.e., horizontally, oreast/west, in the plane of apparatus 50). As such, the horizontal forcecomponent of the rotational movement from inner flexure 24 e may beabsorbed by cantilever 54 a while the vertical force component may betransferred to inner frame 56. One of ordinary skill in the art willappreciate how this example may be adapted for cantilevers 54 b-d andbidirectional comb drive actuators 23 b-d, and will also appreciate thatvarious configurations of cantilevers 54 a-d are within the scope of thedisclosure. In other respects, including, for example, the routing anddistribution of electrical signals, the types of movement that may beachieved, and so on, apparatus 50 may be substantially similar toapparatus 40.

FIGS. 6 and 7 illustrate embodiments of methods 600 and 700. Variousoperations of methods 600 and 700 may be used, for example, to move adevice. The operations of methods 600 and 700 may utilize electrostaticcomb drives to achieve highly precise and efficient movement andpositioning of a device (e.g., that is part of or residing on theplatform) in multiple directions and degrees of freedom and to achievevarious types of movement, such as linear, translations, rotational,diagonal, or mixed movements. Moreover, methods 600 and 700 may beutilized, for example using various MEMS devices and structuresdescribed herein, within a space-constrained environment such as asmartphone. This allows for optical image stabilization and/or autofocuscapabilities that meet the cost, space, and energy demands of suchenvironments, as well as the need for dynamic, flexible, and nimblepositioning and movement. In instances of the present disclosure whereinmethods 600 or 700 are described with regard to the various elements(e.g., bidirectional comb drive actuators 21 a-d) illustrated in any ofthe various figures (e.g., FIG. 4A), it will be understood thatembodiments of method 600 and 700 may use or include various otherelements described with regard to and/or illustrated by FIGS. 1, 2A-2C,3, 4A, 4B, and/or FIG. 5, as will be appreciated by one of skill in theart upon studying the present disclosure.

As illustrated in FIG. 6, method 600 includes, at operation 605,connecting inner frame 46 to one or more bidirectional comb driveactuators 21 a-d. This may be done, for example, using a cantilever 44a-d for each of bidirectional comb drive actuators 21 a-d. At operation610, method 600 includes coupling electrical signals to bidirectionalcomb drive actuators 21 a-d using cantilevers 44 a-d. At operation 615,method 600 includes generating a controlled force using one or morebidirectional comb drive actuators 21 a-d. In one example implementationof method 600, the controlled force effects a movement in a plane (e.g.,in the plane of apparatus 40 or 50), and the movement includes linearmovement. Linear movement may be horizontal, vertical, or diagonal atany number of angles in the plane of apparatus 40 or 50. The movementmay also include rotation movement and/or a combination of linear androtational movement in the plane of apparatus 40 or 50.

Turning now to FIG. 7, which illustrates an operational flow diagram ofmethod 700 in accordance with example embodiments of the presentdisclosure, one embodiment of method 700 includes, at operation 705, oneor more of the operations of method 600. An additional embodiment ofmethod 700 includes, at operation 710, applying the controlled force(see operation 615 of method 600) between inner frame 46 and outer frame48. Yet another embodiment of method 700 includes, at operation 715,mechanically fixing anchor 42 with respect to outer frame 48, andapplying the controlled force to anchor 42.

Bidirectional comb drive actuators 21 a-d, in one embodiment of method700, include first and second comb drives 10 a/b, which, in thisembodiment, each include first and second comb finger arrays 15 a/b and16 a/b. This embodiment of method 700 may include, at operation 720,moving either second comb finger array 15 b and first comb finger array16 a or first comb finger array 15 a and second comb finger array 16 b.

In another embodiment of method 700, bidirectional comb drive actuators21 a-d include flexures 24 a/b. For one or more of bidirectional combdrive actuators 21 a-d, coupling the electrical signals to bidirectionalcomb drive actuators 21 a-d (e.g., at operation 610) includes, in thisinstance, using the flexures 24 a/b to route the electrical signals. Forexample, as described above, flexures 24 a/b may be used to route theelectrical signals between two bidirectional comb drive actuators 21 b/cin apparatus 40.

In general, the various operations of methods 600 and 700 describedherein may be accomplished using or may pertain to components orfeatures of the various systems and/or apparatuses with their respectivecomponents and subcomponents, described herein. Moreover, in variousembodiments, features and functions described herein with regard toFIGS. 1, 2A-2C, 3, 4A, 4B, and 5, may be implemented as or usingoperations of methods (e.g., methods 600 and 700), in addition to beingimplemented as part of systems or apparatuses. As such, the variationsdescribed herein with regard to embodiments and aspects of theapparatuses may be applicable in a substantially similar fashion to theoperations of the methods described herein (e.g., methods 600 and/or700). Upon studying this disclosure, one of skill in the art willrecognize how to implement the disclosed methods using the disclosedapparatuses and/or systems, and vice versa.

The presence of broadening words and phrases such as “one or more,” “atleast,” “but not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent.

Additionally, the various embodiments set forth herein are described interms of example block diagrams, flow charts and other illustrations. Aswill become apparent to one of ordinary skill in the art after readingthis document, the illustrated embodiments and their variousalternatives can be implemented without confinement to the illustratedexamples. For example, block diagrams and their accompanying descriptionshould not be construed as mandating a particular architecture orconfiguration.

While various embodiments of the present disclosure have been describedabove, it should be understood that they have been presented by way ofexample only, and not of limitation. Likewise, the various diagrams maydepict an example architectural or other configuration for thedisclosure, which is done to aid in understanding the features andfunctionality that can be included in the disclosure. The disclosure isnot restricted to the illustrated example architectures orconfigurations, but the desired features can be implemented using avariety of alternative architectures and configurations. Indeed, it willbe apparent to one of skill in the art how alternative functional,logical or physical partitioning and configurations can be implementedto implement the desired features of the present disclosure.Additionally, with regard to flow diagrams, operational descriptions andmethod claims, the order in which the steps are presented herein shallnot mandate that various embodiments be implemented to perform therecited functionality in the same order unless the context dictatesotherwise.

Although the disclosure is described above in terms of various exampleembodiments and implementations, it should be understood that thevarious features, aspects and functionality described in one or more ofthe individual embodiments are not limited in their applicability to theparticular embodiment with which they are described, but instead can beapplied, alone or in various combinations, to one or more of the otherembodiments of the disclosure, whether or not such embodiments aredescribed and whether or not such features are presented as being a partof a described embodiment. Thus, the breadth and scope of the presentdisclosure should not be limited by any of the above-described exampleembodiments, and it will be understood by those skilled in the art thatvarious changes and modifications to the previous descriptions may bemade within the scope of the claims.

What is claimed is:
 1. An apparatus, comprising: a bidirectional combdrive actuator; and a cantilever having first and second conductivelayers for routing electrical signals, the cantilever comprising: afirst end connected to the bidirectional comb drive actuator; and asecond end connected to an inner frame.
 2. The actuator of claim 1,wherein the bidirectional comb drive actuator comprises: first andsecond frame pieces; and first and second comb drives.
 3. The actuatorof claim 2, wherein the first and second comb drives each comprise firstand second comb finger arrays.
 4. The actuator of claim 3, wherein: thefirst comb finger array of the first comb drive is connected to thesecond frame piece; the second comb finger array of the first comb driveis connected to the first frame piece; the first comb finger array ofthe second comb drive is connected to the first frame piece; and thesecond comb finger array of the second comb drive is connected to thesecond frame piece.
 5. The actuator of claim 4, wherein: the first combfinger array of the first comb drive and the second comb finger array ofthe second comb drive are coupled to a first potential; the second combfinger array of the first comb drive is coupled to a second potential;and the first comb finger array of the second comb drive is coupled to athird potential.
 6. The actuator of claim 5, wherein the firstconductive layer is electrically coupled to the second potential and thesecond conductive layer is electrically coupled to the third potential.7. The actuator of claim 1, wherein the first conductive layer iselectrically isolated from the second conductive layer.
 8. The actuatorof claim 7, wherein the first conductive layer routes a first of theelectrical signals to the bidirectional comb drive actuator and thesecond conductive layer routes a second of the electrical signals to thebidirectional comb drive actuator.
 9. The actuator of claim 1, whereinthe bidirectional comb drive actuator comprises: two or more combdrives, each of the comb drives comprising first and second curved combfinger arrays; an inner flexure connected to the first end one of thecantilevers; and a pair of outer flexures on opposite sides of the innerflexure.
 10. A multi-directional actuator for moving a device, themulti-directional actuator comprising: one or more bidirectional combdrive actuators, each of the bidirectional comb drive actuatorscomprising: two or more comb drives, each of the comb drives comprisingfirst and second comb finger arrays; and first and second frame pieces;wherein the first comb finger array of the first comb drive and thesecond comb finger array of the second comb drive are connected to thesecond frame piece, and wherein the second comb finger array of thefirst comb drive and the first comb finger array of the second combdrive are connected to the first frame piece.
 11. The actuator of claim10, further comprising an inner frame connected to the bidirectionalcomb drive actuators by one or more cantilevers, each of the cantileverscomprising routing for a first electrical signal, at least one of thecantilevers further comprising routing for a second electrical signal.12. The multi-directional actuator of claim 10, further comprising anouter frame connected to the inner frame by one or more spring elements,wherein the bidirectional comb drive actuators are attached to a centralanchor that is mechanically fixed with respect to the outer frame. 13.The multi-directional actuator of claim 11, wherein a platformmechanically fixes the central anchor with respect to the outer frame;and wherein the platform is selected from the group consisting of anoptoelectronic device and an image sensor.
 14. The multi-directionalactuator of claim 12, wherein, for each of the bidirectional comb driveactuators: the cantilever electrically couples the bidirectional combdrive actuator to one or more contact pads disposed on the inner frame;and the spring elements electrically couple the contact pads disposed onthe inner frame to one or more corresponding contact pads disposed onthe outer frame.
 15. A method, comprising: connecting an inner frame toone or more bidirectional comb drive actuators using a cantilever foreach of the bidirectional comb drive actuators; coupling electricalsignals to the bidirectional comb drive actuators using the cantilevers;generating a controlled force using the bidirectional comb driveactuators and the electrical signals.
 16. The method of claim 15,wherein each of the bidirectional comb drive actuators comprises firstand second comb drives, and wherein the first and second comb driveseach comprise first and second comb finger arrays; and furthercomprising moving, in response to applying the controlled force, eitherthe second comb finger array of the first comb drive and the first combfinger array of the second comb drive, or the first comb finger array ofthe first comb drive and the second comb finger array of the second combdrive.
 17. The method of claim 15, wherein the controlled force effectsmovement in a plane; and wherein the movement comprises linear movement.18. The method of claim 15, wherein the controlled force effectsmovement in a plane; and wherein the movement comprises rotationalmovement.
 19. The method of claim 15, further comprising: applying thecontrolled force between an outer frame and an inner frame; andmechanically fixing an anchor with respect to the outer frame, whereinthe controlled force is applied to the anchor.
 20. The method of claim15, wherein the bidirectional comb drive actuators comprise flexures;and wherein, for one or more of the bidirectional comb drive actuators,coupling the electrical signals to the bidirectional comb driveactuators comprises using the flexures to route the electrical signals.